rs1000b@yahoo.com
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 Posted: Fri Oct 10, 2008 11:17 pm Post subject: Long-term effects of calorie or protein restriction on serum |
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Aging Cell. 2008 Oct;7(5):681-7.
Long-term effects of calorie or protein restriction on serum IGF-1 and
IGFBP-3 concentration in humans.
Fontana L, Weiss EP, Villareal DT, Klein S, Holloszy JO.
Division of Geriatrics & Nutritional Sciences, Washington University
School of Medicine, St Louis, MO 63110, USA. lfontana@@@@dom.wustl.edu
Reduced function mutations in the insulin/IGF-I signaling pathway
increase maximal lifespan and health span in many species. Calorie
restriction (CR) decreases serum IGF-1 concentration by ~40%, protects
against cancer and slows aging in rodents. However, the long-term
effects of CR with adequate nutrition on circulating IGF-1 levels in
humans are unknown. Here we report data from two long-term CR studies
(1 and 6 years) showing that severe CR without malnutrition did not
change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans. In contrast,
total and free IGF-1 concentrations were significantly lower in
moderately protein-restricted individuals. Reducing protein intake
from an average of 1.67 g kg(-1) of body weight per day to 0.95 g
kg(-1) of body weight per day for 3 weeks in six volunteers practicing
CR resulted in a reduction in serum IGF-1 from 194 ng mL(-1) to 152 ng
mL(-1). These findings demonstrate that, unlike in rodents, long-term
severe CR does not reduce serum IGF-1 concentration and IGF-1 :
IGFBP-3 ratio in humans. In addition, our data provide evidence that
protein intake is a key determinant of circulating IGF-1 levels in
humans, and suggest that reduced protein intake may become an
important component of anticancer and anti-aging dietary
interventions.
PMID: 18843793 [PubMed - in process] |
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jc101
Guest
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| Posted: Sat Oct 11, 2008 3:30 pm Post subject: Re: Long-term effects of calorie or protein restriction on s |
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On Oct 10, 6:17 pm, "rs10...@yahoo.com" <rs10...@yahoo.com> wrote:
[quote]Aging Cell. 2008 Oct;7(5):681-7.
Long-term effects of calorie or protein restriction on serum IGF-1 and
IGFBP-3 concentration in humans.
Fontana L, Weiss EP, Villareal DT, Klein S, Holloszy JO.
Division of Geriatrics & Nutritional Sciences, Washington University
School of Medicine, St Louis, MO 63110, USA. lfontana@@@@dom.wustl.edu
Reduced function mutations in the insulin/IGF-I signaling pathway
increase maximal lifespan and health span in many species. Calorie
restriction (CR) decreases serum IGF-1 concentration by ~40%, protects
against cancer and slows aging in rodents. However, the long-term
effects of CR with adequate nutrition on circulating IGF-1 levels in
humans are unknown. Here we report data from two long-term CR studies
(1 and 6 years) showing that severe CR without malnutrition did not
change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans. In contrast,
total and free IGF-1 concentrations were significantly lower in
moderately protein-restricted individuals. Reducing protein intake
from an average of 1.67 g kg(-1) of body weight per day to 0.95 g
kg(-1) of body weight per day for 3 weeks in six volunteers practicing
CR resulted in a reduction in serum IGF-1 from 194 ng mL(-1) to 152 ng
mL(-1). These findings demonstrate that, unlike in rodents, long-term
severe CR does not reduce serum IGF-1 concentration and IGF-1 :
IGFBP-3 ratio in humans. In addition, our data provide evidence that
protein intake is a key determinant of circulating IGF-1 levels in
humans, and suggest that reduced protein intake may become an
important component of anticancer and anti-aging dietary
interventions.
PMID: 18843793 [PubMed - in process]
[/quote]
The CR test subjects were only 20% calorie reduced, and the second
test was of Calorie Restriction Society members who had consumed 1800
cal/day for years - 28% reduction. No IGF axis changes compared to
controls in either group.
This is why so called "moderate" CR is useless, you have to get to
that 40% reduction of calories (male about 1500 calories max) to pump
up respiration, improve mito function with reduced ROS, and lower IGF
axis. "Moderate CR" is merely a recipe for frailty/osteopenia-
osteoporosis/psych problems and average lifespan.
1500 calories per day for Effective CR, what is that, a BMI of 16 ?
Have fun.
JLC |
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